This year marks the 50th anniversary of the great "March on Washington for Jobs and Freedom". It was there, at one of the largest rallies for human rights, that Dr. Martin Luther King Jr. delivered his famous 'I Have a Dream' speech.

On August 28, 1963, Dr. King and all those gathered in Washington, D.C., addressed the notion of greater equality and justice in America in a way which could no longer be ignored. Thanks to Dr. King's unyielding work, and the work of countless others before and after him, laws like the Voting Rights Act of 1965 were eventually passed, and victories were achieved in the struggle for civil rights.

In the time since, we've watched people of color break down barriers across the board - including into the highest office of the land. Progress over the last five decades is undeniable. But now 50 years after the "March on Washington", we are dangerously close to regressing on some of the most fundamental advancements in our society.

The Supreme Court of the United States is set to rule on several key items this year that are at the core of justice and equality in America. Shelby v. Holder challenges Section 5 of the Voting Rights Act itself. A key aspect of the Act, Section 5 requires jurisdictions that have a history of discriminatory voting practices to obtain advanced approval from the federal government before they can alter election laws.

Without Section 5, the basic foundation of the Voting Rights Act would be destroyed. The floodgates of biased and disenfranchising practices like harsh new voter ID laws would open and the protection of our participation in the voting process would be eliminated. Voting rights for all American citizens was a basic principle of Dr. King and all those who sacrificed during the civil rights struggle and in subsequent years. Ironically, half a century after Dr. King's speech, voter equality is under attack all over again.

In addition to the Voting Rights Act, one of the greatest advancements toward equality we achieved in this nation was the ability of those who were traditionally excluded from higher learning to attend our great colleges and universities. Well, in 2013, affirmative action hangs in the balance. Two cases, Fisher v. University of Texas and a Michigan law banning affirmative action in public college admissions, have reached the Supreme Court.

The outcome of these two cases will have serious ramifications for the admission practices of schools throughout the country. At a time when our educational system is severely leaving minority and poor students behind, some are attempting to eliminate laws designed to create a more even playing field. Our society is growing ever diverse, and our institutions of higher learning need to reflect that diversity. Affirmative action doesn't mean preferential treatment; it means equalizing an imbalanced scale. The future of so many students remains in limbo as the high court weighs in this year on these crucial cases.

This year marks another milestone in this nation's history: the 150th anniversary of the Emancipation Proclamation. In the last 150 years, we've witnessed momentous progress that was achieved only because of the selfless acts of many. Folks have marched, rallied, organized, boycotted, withstood beatings, bombings, water hoses, dogs and some even died for the cause of justice.

In a post-civil rights era, laws such as the Voting Rights Act and affirmative action appeared etched in stone permanently. But now the state of justice and equality in America remains to be determined because of these renewed attempts to repeal such laws. We can either continue on a path toward greater freedom for all, or regress back to the wrong side of history.

The generation of Dr. King, and the generation immediately behind him continued fighting until they got voting rights and affirmative action on the books. We must not become the generation that couldn't sustain and maintain it.

Rev. Al Sharpton is president/CEO of the National Action Network and host of PoliticsNation on MSNBC. This article - the sixteenth of a 20-part series - is written in commemoration of the 50th Anniversary of the Lawyers' Committee for Civil Rights Under Law, of which Congressman Lewis is grand marshal. The Lawyers' Committee is a nonpartisan, nonprofit organization, formed in 1963 at the request of President John F. Kennedy to enlist the private bar's leadership and resources in combating racial discrimination and the resulting inequality of opportunity - work that continues to be vital today. For more information, please visit www.lawyerscommittee.org.